Dark Matter signals at the LHC from a 3HDM

• Published in: The journal of high energy physics 2018-05, Vol.2018 (5), p.1-44, Article 30
• Main Authors: Cordero, A., Hernandez-Sanchez, J., Keus, V., King, S. F., Moretti, S., Rojas, D., Sokolowska, D.
• Format: Article
• Language: English
• Subjects: Beyond Standard Model; Classical and Quantum Gravitation; Dark matter; Decay; Elementary Particles; Hadron-Hadron scattering (experiments); Higgs bosons; Higgs physics; High energy physics; Large Hadron Collider; Leptons; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Experimental Physics; Relativity Theory; Scalars; String Theory; Superconducting supercolliders
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP05(2018)030

A bstract We analyse new signals of Dark Matter (DM) at the Large Hadron Collider (LHC) in a 3-Higgs Doublet Model (3HDM) where only one doublet acquires a Vacuum Expectation Value (VEV), preserving a parity Z 2 . The other two doublets are inert and do not develop a VEV, leading to a dark scalar sector controlled by Z 2 , with the lightest CP-even dark scalar H 1 being the DM candidate. This leads to the loop induced decay of the next-to-lightest scalar, H 2 → H 1 f f ¯ f = u , d , c , s , b , e , μ , τ , mediated by both dark CP-odd and charged scalars. This is a smoking-gun signal of the 3HDM since it is not allowed in the 2HDM with one inert doublet and is expected to be important when H 2 and H 1 are close in mass. In practice, this signature can be observed in the cascade decay of the SM-like Higgs boson, h → H 1 H 2 → H 1 H 1 f f ¯ into two DM particles and di-leptons/di-jets, where h is produced from either gluon-gluon Fusion (ggF) or Vector Boson Fusion (VBF). However, this signal competes with the tree-level channel q q ¯ → H 1 H 1 Z ∗ → H 1 H 1 f f ¯ . We devise some benchmarks, compliant with collider, DM and cosmological data, for which the interplay between these modes is discussed. In particular, we show that the resulting detector signature, , with invariant mass of f f ¯ much smaller than m Z , can potentially be extracted already during Run 2 and 3. For example, the H 2 → H 1 γ * and γ * → e + e − case will give a spectacular QED mono-shower signal.